I haven't actually tried the demo so I don't actually know how good or bad the writing is. I guess I will download the demo. I was going to wait until it was finished, but if they really want to make the chapters as long as you say the first chapter is, then its going to be a looooooong time before the game is ever completed.
Aside from some stilted grammar, I didn't think the quality of the writing was too bad. Katawa Shoujo probably has more potential than the majority of fan-made efforts.
But yeah, there's an amazing
amount of bloat (filler scenes, lots of repetition, characters saying unnecessary and often uninteresting things, etc.) and a poor sense of how to pace a story. Aggressive editing is required for any of the potential to be realized.